A toilet apparatus including a functional component has been known. The functional component includes a washing device washing an ano-genital region of a human body and a casing housing the washing device. JP 2016-43138 A (Kokai) discusses a toilet bowl device including a toilet seat hiding a functional component and a hinge mechanism and making view from the exterior impossible for suppressing adhesion of foreign mater such as dust or the like to the functional component and the hinge mechanism.
However, according to the technique discussed in JP 2016-43138 A (Kokai), although the adhesion of the foreign matter to the functional component can be suppressed, a size of toilet seat increases excessively, and usability is not good.
The invention has been made on the basis of recognition of such a problem, the purpose is to provide a toilet apparatus which can suppress the adhesion of the foreign matter to a member in which the washing device is housed while suppressing the size increase and deterioration of the usability.